(19)
(11) EP 1 049 353 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
26.01.2005 Bulletin 2005/04

(43) Date of publication A2:
02.11.2000 Bulletin 2000/44

(21) Application number: 00108816.0

(22) Date of filing: 26.04.2000
(51) International Patent Classification (IPC)7: H04R 3/00, H04R 9/06
(84) Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
Designated Extension States:
AL LT LV MK RO SI

(30) Priority: 26.04.1999 JP 11785299
25.11.1999 JP 33377799

(71) Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
Kadoma-shi, Osaka 571-8501 (JP)

(72) Inventor:
  • Tanaka, Shoji
    Chuo-ku, Kobe-shi, Hyogo 650-0004 (JP)

(74) Representative: Stippl, Hubert, Dipl.-Ing. 
Hafner & Stippl, Patentanwälte, Schleiermacherstrasse 25
90491 Nürnberg
90491 Nürnberg (DE)

   


(54) Bass reproduction speaker apparatus


(57) Negative stiffness is generated for a vibration system of a speaker unit (131) by using a movable magnet (133) attached to the vibration system of the speaker unit (131) and also a ring-like stationary magnet (134) arranged coaxially at the outer radius thereof in order to increase equivalently internal volume of a cabinet (132). In addition, an offset in the displacement direction of the vibration system of the speaker unit (131) is detected with a Hall element (135) and fed back to a power amplifier (136) in order to correct the offset in the displacement direction of the vibration system of the speaker unit (131). As a result, a reliable and practical bass reproduction speaker apparatus can be obtained, and the speaker apparatus is noise-free and excellent in bass reproduction performance even with a cabinet of small capacity.






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